diff --git a/platform/external-system-api/src/com/intellij/openapi/externalSystem/model/project/ContentRootData.java b/platform/external-system-api/src/com/intellij/openapi/externalSystem/model/project/ContentRootData.java
index e1b199cd1b9f..fb54cd26d461 100644
--- a/platform/external-system-api/src/com/intellij/openapi/externalSystem/model/project/ContentRootData.java
+++ b/platform/external-system-api/src/com/intellij/openapi/externalSystem/model/project/ContentRootData.java
@@ -9,6 +9,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
+import java.io.Serializable;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Locale;
@@ -97,7 +98,7 @@ public class ContentRootData extends AbstractExternalEntityData {
     return buffer.toString();
   }
 
-  public static class SourceRoot {
+  public static class SourceRoot implements Serializable {
     @NotNull
     private final String myPath;